Out of all the nutrients a person eats, the most confusing is probably fat.
While some people try to take in as little fat as possible in an attempt to stay slim, the body needs fat in order to function correctly. If too much fat is taken in, however, it can cause obesity. Obesity is a major risk factor for a number of diseases, including cancer.
Now, thanks to new research reported in Nature, scientists have figured out how a high-fat diet can lead to colon cancer.
Because of all the toxins they're exposed to, the intestines are constantly making new cells from stem cells to repair themselves. The researchers found that high-fat diets change the environment inside the intestines, making it more likely for these rapidly-dividing cells to mutate and form tumors.
"Not only does the high-fat diet change the biology of stem cells, it also changes the biology of non-stem-cell populations, which collectively leads to an increase in tumor formation," principal investigator Omer Yilmaz from MIT explained in a news release.
The diet of the mice used in the study was 60% fat, while a control group were fed a more balanced diet. As a comparison, the recommended fat intake for an adult human is 20-30%. Not only did the mice on this diet end up with 30-50% more body mass, but also significantly higher rates of colon cancer.
Through analysis of the intestinal tissue, the scientists determined that the breakdown occurred on the level of cellular communication. Cells in the intestines get cues from one another to keep their growth in check. When the gut environment changes due to a high-fat diet, the cells can't communicate properly and their growth runs amok.
"You have more stem cells and they're able to operate independent of inputs coming from their microenvironment," Yilmaz explained.
This finding could pave the way for new tests to diagnose the disease in its early stages — a key to increasing the odds of survival — as well as new treatments.
As obesity rates continue to climb around the world, it's increasingly important to understand the link between diet and disease. Last fall, for instance, the World Health Organization declared fatty, processed meats like bacon and sausage as known carcinogens.
This study further reminds us that diet plays a crucial role in our health, and that the health risks associated with obesity should not be ignored.
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